CN117744067B - Access space switching method, device, processor, equipment and storage medium - Google Patents

Abstract

The present disclosure provides an access space switching method, device, processor, equipment and storage medium. The method determines the access space to be switched based on the received access parameters, and jumps from the current access space to EL3; in EL3, the context of the current access space is saved, and the access space switching setting is performed, and the context of the current access space is restored after the setting is completed, and the running program of the access space to be switched is determined based on the restored context of the current access space; the running program of the secure space and the running program of the non-secure space use a set of codes; based on the running program of the access space to be switched and the switching setting, enter the access space to be switched. By using a set of codes to simulate the running program of the secure space and the running program of the non-secure space, there is no need to set different stacks, running programs and operating systems for different access spaces, which is simpler in implementation and reduces the workload of developers.

Description

Access space switching method, device, processor, equipment and storage medium

Technical Field

The present disclosure relates to the field of secure access technology, and in particular to an access space switching method, apparatus, processor, device and storage medium.

Background technique

For the processor security access scenario of the ARMv8 aarch64 architecture, as shown in Figure 1, the TrustZONE (TZ) mechanism is used to divide the system into non-secure space (Non-secure state/Normal world/REE) and secure space (Secure state/Secure world/TEE), and a processor mode called monitor mode (Secure Monitor, also known as secure monitor) is introduced on the basis of non-secure space and secure space, so that the non-secure space and secure space can switch freely with each other through the secure monitor mode. On the basis of the above TZ architecture, considering that each component of the non-secure space and the secure space has different permission levels to access the system and processor resources, the exception levels (EL) in the Trusted Firmware (TF) solution are introduced to further divide it, specifically: divided into four levels: EL0, EL1, EL2, and EL3. Among them, ordinary APP runs in EL0; while EL1 generally runs the operating system or underlying software; EL2 provides support for virtualization, which can be not implemented; EL3 provides switching between secure space and non-secure space and other advanced functions.

For the current hardware verification, it does not involve complex operating systems and task scheduling, etc., but focuses more on register configuration/hardware path analysis, etc. Therefore, the current hardware verification is generally non-secure access and does not involve secure access. However, with the advancement of technology, in some security scenarios (such as confidential computing and digital rights management), for peripherals, in order to ensure security (such as fingerprint verification), some registers are private and cannot be directly accessed by ordinary apps (such as WeChat), otherwise it will trigger an exception or the return value content will not meet expectations. Therefore, some hardware verification scenarios also need to involve secure access, but the current hardware verification firmware code does not support secure access, nor does it involve switching between non-secure access and secure access. If the access method of the secure space or non-secure space in the existing product delivery form is adopted, it is necessary to implement or transplant the complete stack/code/processing logic in EL0/EL1/EL3 and the related secure boot process, which has the problems of huge workload and high software design capability requirements.

Among them, the ARM (Advanced RISC Machines) architecture is a reduced instruction set (RISC) processor architecture. The X in ARMvX refers to the ARM instruction set and architecture version. ARMv8 is the first generation of instruction set and architecture that supports 64-bit processors. ARMv8 has two execution states, aarch64: 64-bit execution state, aarch32: 32-bit execution state.

Summary of the invention

The purpose of the present disclosure is to provide an access space switching method, apparatus, processor, device and storage medium to simplify the workload of switching between a secure space and a non-secure space.

According to one aspect of the present disclosure, there is provided an access space switching method, including:

Determine the access space to be switched based on the received access parameters, and jump from the current access space to EL3; the access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces;

In EL3, the context of the current access space is saved, and the access space switching setting is performed. After the setting is completed, the context of the current access space is restored, and based on the restored context of the current access space, the running program of the access space to be switched is determined; the running program of the secure space and the running program of the non-secure space use a set of codes;

Based on the running programs and switching settings of the access space to be switched, enter the access space to be switched.

Furthermore, the access space switching method further includes:

Before switching the access space, the firmware stack is set for the secure space and the non-secure space.

Furthermore, the firmware stack is set for the secure space and the non-secure space, including:

Set the stack of the secure space and the stack of the non-secure space to the same stack.

Furthermore, the firmware stack settings for the secure space and the non-secure space also include:

Configure the same MMU page tables for secure and non-secure spaces.

Furthermore, the same MMU page table is configured for the secure space and the non-secure space, including:

Set the NS bit in the MMU page table to 0.

Further, the context includes a relevant register value of the current access space, and based on the restored context of the current access space, determining the running program of the access space to be switched includes:

Obtaining the address of the current running program in the current access space based on the relevant register value of the current access space;

The running program of the access space to be switched is obtained based on the address of the current running program.

Furthermore, the switching setting of the access space includes:

According to the type of access space to be switched, the NS bit of the SCR_EL3 register is set; if the NS bit of the SCR_EL3 register is set to 0, it indicates the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it indicates the access behavior of the non-secure space.

According to another aspect of the present disclosure, the present disclosure provides an access space switching device, including:

An access space determination module, used to determine the access space to be switched based on the received access parameters, and jump from the current access space to EL3; the access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces;

An access space switching setting module is used to save the context of the current access space in EL3, and perform access space switching settings, restore the context of the current access space after the settings are completed, and determine the running program of the access space to be switched based on the restored context of the current access space; the running program of the secure space and the running program of the non-secure space use a set of codes;

The access space switching module is used to enter the access space to be switched based on the running program and switching settings of the access space to be switched.

Furthermore, the access space switching device also includes:

The initialization setting module is used to set the firmware stack for the secure space and the non-secure space before switching the access space.

Furthermore, the initialization setting module is also used to set the stack of the secure space and the stack of the non-secure space to be the same stack.

Furthermore, the initialization setting module is also used to configure the same MMU page table for the secure space and the non-secure space.

Furthermore, the initialization setting module is also used to set the NS bit in the MMU page table to 0.

Further, the context includes the relevant register value of the current access space, and the access space switching setting module is also used to obtain the current running program address of the current access space based on the relevant register value of the current access space;

The running program of the access space to be switched is obtained based on the address of the current running program.

Furthermore, the access space switching setting module is also used to set the NS bit of the SCR_EL3 register according to the type of access space to be switched; if the NS bit of the SCR_EL3 register is set to 0, it indicates the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it indicates the access behavior of the non-secure space.

According to another aspect of the present disclosure, a processor is provided, which is divided into a secure space, a non-secure space and EL3, and the processor switches between the secure space and the non-secure space based on the access space switching method described in any of the above embodiments.

According to another aspect of the present disclosure, an electronic device is provided, comprising the processor described in any one of the above embodiments.

According to another aspect of the present disclosure, an electronic device is provided, comprising the electronic device described in any one of the above embodiments.

According to another aspect of the present disclosure, a storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the access space switching method described in any of the above embodiments are implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a processor architecture in the prior art;

FIG2 is a schematic diagram of a flow chart of an access space switching method provided by an embodiment of the present disclosure;

FIG3 is a schematic diagram of the structure of an access space switching device provided by an embodiment of the present disclosure.

Detailed ways

Before introducing the embodiments of the present disclosure, it should be noted that:

Some embodiments of the present disclosure are described as processing flows. Although the various operation steps of the flow may be given sequential step numbers, the operation steps therein may be implemented in parallel, concurrently or simultaneously.

In the embodiments of the present disclosure, the terms "first", "second", etc. may be used to describe various features, but these features should not be limited by these terms. These terms are used only to distinguish one feature from another.

The term “and/or” may be used in embodiments of the present disclosure. “And/or” includes any and all combinations of one or more of the associated features listed.

It should be understood that when describing the connection or communication relationship between two components, unless it is explicitly stated that the two components are directly connected or directly communicating, the connection or communication between the two components can be understood as direct connection or communication, or as indirect connection or communication through an intermediate component.

In order to make the technical solutions and advantages of the embodiments of the present disclosure more clearly understood, the exemplary embodiments of the present disclosure are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

The purpose of the present disclosure is to provide a simplified access space switching method. Since the existing switching method between a secure space and a non-secure space sets corresponding stacks for the secure space and the non-secure space respectively during implementation, the running program of the secure space is saved in the stack corresponding to the secure space, and the running program of the non-secure space is saved in the stack corresponding to the non-secure space, that is, the running program of the secure space and the running program of the non-secure space are two sets of codes. For example, if the current program is running in EL1 of the non-secure space, and an interrupt that is intended to be processed by EL1 of the secure space comes, then EL1 of the non-secure space will call SMC (secure monitor call) to enter EL3, that is, this step is implemented by the program of EL1 of the non-secure space + the stack of the non-secure space; after entering EL3, EL3 saves the context of the non-secure space and performs the switch setting of the access space. After the setting is completed, the context of the secure space is restored, and the ERET (Exception Return) instruction is used to enter EL1 of the secure space, that is, this step is implemented by the program of EL3 + the stack of EL3; after entering EL1 of the secure space, EL1 of the secure space performs relevant processing, that is, this step is implemented by the program of EL1 of the secure space + the stack of the secure space. And when executing running programs in different spaces, the operating systems used will also be different, for example, EL1 of the secure space uses OPTEE, EL1 of the non-secure space uses LINUX, and EL3 uses ATF (ARM trusted firmware); among them, OPTEE is a dual-core operating system that supports Trustzone technology under the ARM architecture.

The present disclosure sets the stack of the secure space and the stack of the non-secure space to the same stack, and the running program of the secure space and the running program of the non-secure space also use the same set of codes. By using a set of codes, the running program of the secure space and the running program of the non-secure space are simulated; that is, the present disclosure actually obtains the running program from the same stack in the EL1 of the non-secure space and the EL1 of the secure space, and the running program also uses the same set of codes; the specific implementation is that in EL3, the context saved by EL3 and the context restored are the relevant contents of the same set of codes, but the saved context is used to indicate the running program of the current access space, and the restored context is used to indicate the running program of the access space to be switched; because a set of codes is used, the operating system only needs to use one. Compared with the existing switching method between the secure space and the non-secure space, the switching scheme of the present disclosure does not need to set different stacks, running programs and operating systems for different access spaces, which is simpler in implementation and reduces the workload of developers. At the same time, the EL3 of the present disclosure only needs to implement the functions of space switching and context saving, and does not need to implement other functions, so the code of the EL3 of the present disclosure is also more concise than the existing EL3 code.

An embodiment of the present disclosure provides an access space switching method, as shown in FIG2 , the access space switching method includes the following steps:

Step 101: Determine the access space to be switched based on the received access parameters, and jump from the current access space to EL3;

Step 102: In EL3, save the context of the current access space, and perform access space switching settings. After the settings are completed, restore the context of the current access space, and determine the running program of the access space to be switched based on the restored context of the current access space;

Step 103: Enter the access space to be switched based on the running program and switching settings of the access space to be switched.

The access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces; the running program of the secure space and the running program of the non-secure space use a set of codes.

It should be understood that the processor based on the ARMv8 aarch64 architecture uses the TRUSTZONE mechanism to divide it into non-secure space, secure space and EL3, and the non-secure space and secure space are further divided by introducing the EL in the trusted firmware solution, and the non-secure space and secure space are further divided into EL0, EL1 and EL2. The processor can be a CPU (Central Processing Unit), GPU (graphics processing unit) and MCU (Micro Control Unit) of the system on chip of the ARMv8aarch64 architecture.

In one implementation, if the program is currently running normally in EL1 of the non-secure space, the firmware code can input access parameters by calling the interface. The interface determines whether the access parameter is non-secure access or secure access. If it is secure access, the access space to be switched is determined to be the secure space. If it is non-secure access, the access space to be switched is determined to be the non-secure space.

If the access space to be switched is determined to be EL1 of the secure space based on the received access parameters, and the current access space is EL1 of the non-secure space; then the EL1 of the non-secure space will call the SMC instruction. Since SMC is a jump from EL1/2 to EL3, it will jump to the interrupt vector table of EL3, and the access parameters will be stored in the ISS field of the ESR_EL3 register. ESR_EL3 is a register of ARMV8, and ISS is a field of ESR_EL3. If the "SMC X" instruction occurs, X will be stored in the ISS field; where X is the parameter of the SMC instruction, and X is determined based on the access parameters. Therefore, the value of X can be set by whether the access space to be switched is a secure space or a non-secure space, and the parameters can be passed through ISS; the value of X can be set to 0 to indicate that the access space to be switched is a secure space, and the value of X can be set to 1 to indicate that the access space to be switched is a non-secure space.

EL3 recognizes that this is an SMC instruction, and it was previously running in the non-secure space EL1, so it calls the interrupt handling function (for example, the SYNC handling function EL3_SYNC_HANDLER), and the interrupt handling function saves the context of the current access space through assembly instructions; after saving, it jumps to the C handling function (for example, the C handling function of EL3_L64SYNC), and the C handling function reads the value of the ISS field in the ESR_EL3 register. If the value is 0, it recognizes that it is going to enter the secure space at this time, so it performs the access space switching setting, and exits to the interrupt handling function after the setting is completed.

Since the running program in the secure space and the running program in the non-secure space use a set of codes, the previously saved context is directly restored to determine the running program in the access space to be switched; then the ERET instruction is triggered to enter the access space to be switched.

In the present disclosure, the context includes the relevant register value of the current access space, the current running program address of the current access space is obtained based on the relevant register value of the current access space, and the running program of the access space to be switched is obtained based on the current running program address.

It should be understood that since the running program of the secure space and the running program of the non-secure space use a set of codes, the running program of the secure space and the running program of the non-secure space are at different locations in the set of codes. The current running program address can be understood as the current address of the running program of the non-secure space when switching from the non-secure space to the secure space; the running program address of the secure space can be obtained based on the current running program address, and the running program of the secure space can be obtained based on the running program address of the secure space. Among them, when switching from the non-secure space to the secure space, the hardware will automatically save the PC (instruction) to the ELR_EL1 register, and after ERET, the hardware will restore the PC value from ELR_EL1; because in the assembly instruction, the PC pointer indicates which instruction to execute, so based on the PC value of the non-secure space, it can be known that after switching to the secure space, the running program address of the secure space, that is, it knows which assembly instruction to execute next.

Of course, this embodiment is only an example of the present disclosure. The method of obtaining the running program of the access space to be switched based on the address of the current running program is not limited to this, and can also be set according to actual conditions. If the verification requirements for the secure access scenario only focus on whether the behavior of the peripheral meets expectations; such as only focusing on whether the switching operation between non-secure access and secure access is performed, without paying attention to the specific access function; when generating code, there is no need to specifically specify which codes are running programs in the secure space and which codes are running programs in the non-secure space; and when performing the access space switching operation, the method of obtaining the running program of the access space to be switched only needs to add 1 to the current running program address, as long as it is ensured that different codes are running before and after the access space switching setting; that is, it is only necessary to ensure that the access space is switched.

In the present disclosure, the switching setting of the access space includes: setting the NS bit of the SCR_EL3 register according to the type of access space to be switched; if the NS bit of the SCR_EL3 register is set to 0, it represents the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it represents the access behavior of the non-secure space.

It should be understood that the C processing function of EL3 determines the type of access space to be switched according to the value of the ISS field in the ESR_EL3 register. When it recognizes that it is time to enter the secure space, it sets the NS BIT in the SCR_EL3 register to 0. After the setting is completed, it exits to the interrupt processing function.

In the process of switching the access space, in addition to setting the NS BIT in the SCR_EL3 register, the MMU (memory management unit) page table needs to be configured. Since the prior art sets corresponding stacks for the secure space and the non-secure space respectively, and the running programs of the secure space and the non-secure space are two sets of codes, the secure space and the non-secure space are also configured with MMU page tables respectively, that is, the MMU page tables are configured as two.

In order to simplify the switching method between the secure space and the non-secure space, the present disclosure configures the same MMU page table for the secure space and the non-secure space, that is, only one MMU page table is configured. The NS bit in the MMU page table is set to 0, which indicates that the access initiated to the secure space is valid.

In the process of switching the access space, in order to ensure that the access model meets expectations, you need to set the NS BIT in the SCR_EL3 register first, and then configure the MMU page table. Setting the NS BIT in the SCR_EL3 register to 0 indicates access to the secure space. When the NS BIT in the SCR_EL3 register is set to 0, in order to ensure that the access initiated to the secure space is valid, the NS bit of the MMU page table must also be set to 0; that is, the NS BIT in the SCR_EL3 register is set to 0, and the NS bit of the MMU page table is set to 0, in order to smoothly switch from the non-secure space to the secure space. If switching from the secure space to the non-secure space is performed, you only need to ensure that the NS BIT in the SCR_EL3 register is set to 1. The value of the NS bit of the MMU page table is invalid when the NS BIT in the SCR_EL3 register is set to 1.

Therefore, in order to simplify the switching process, when setting the firmware stack, that is, when performing the initial setting, the NS bit in the MMU page table is set to 0. Each time the access space is switched, it is only necessary to set the NSBIT in the SCR_EL3 register. Since the NS bit in the MMU page table is fixedly set to 0, there is no need to operate the MMU page table each time the access space is switched, which simplifies the access space switching process.

In the present disclosure, the switching process from secure space to non-secure space is basically the same as the switching process from non-secure space to secure space. The only difference is that the value of the access parameter is different, and when the access space switching setting is performed, the value set for the NS BIT in the SCR_EL3 register is also different. The rest of the processes are the same.

In the present disclosure, before switching the access space, it is necessary to set the firmware stack for the secure space and the non-secure space, and set the stack of the secure space and the stack of the non-secure space to the same stack. The running program of the secure space and the running program of the non-secure space are kept in the same stack, thereby realizing that the running program of the secure space and the running program of the non-secure space use a set of codes.

Before switching the access space, the present disclosure also needs to perform initialization settings. For the EL3 of the present disclosure, it is only necessary to implement the switching function and the functions of saving and restoring the context. The basic requirements for supporting the switching function and the functions of saving and restoring the context are: providing SMC instruction support + SMC interrupt support (i.e. interrupt vector table + corresponding processing function) + function/local variable support (i.e. EL3 stack) + mode switching (i.e. supporting the NS BIT setting of the ESR_EL3 register in the C processing function). Therefore, in order to support the switching function of EL3 and the functions of saving and restoring the context, the present disclosure supports each basic requirement during initialization.

To support the SMC instruction, the SMD in the SCR_EL3 register is turned off and the NS in the SCR_EL3 register is set to 1.

To support SMC interrupts, the interrupt vector table EL3_Vectors of EL3 is configured to the interrupt processing function VBAR_EL3 of EL3. For the interrupt processing function in EL3_Vectors, based on the DEN0024A_v8_architecture_PG document (an official document of ARM V8), it can be seen that it is divided into 4 groups, each group has 4 entries, which are used to handle different inputs of different types of EL. For this disclosure, because EL1 runs in the Aarch64 execution state and the SMC instruction is a synchronous/Synchronous instruction, it is only necessary to implement the interrupt processing function corresponding to the first entry (Synchronous) in the third group (Lower EL using AArch64); the mode switching function is implemented in the interrupt processing function.

To support functions/local variables, the EL3 stack configured in the link file is loaded so that function input parameters/local variables can have corresponding stacks for entry/exit. For this operation, you only need to load the address of the EL3 stack configured in the stack settings into sp through the LDR instruction.

The stack of EL3 can be set as: EL3_STACK +0 ALIGN 16 EMPTY 0x800, where EL3_STACK is the name of the stack, +0 means it follows the previous stack, ALIGN 16 means 16-byte alignment, EMPTY means default zero filling, and 0x800 is the stack size. The stack of EL3 can be increased by indicating that EL3_STACK follows the previous stack (such as EL1_STACK), 16-byte alignment and size 0x800, and all zeros.

Based on the same inventive concept, an embodiment of the present disclosure further provides an access space switching device, which may include an access space determining module 201, an access space switching setting module 202 and an access space switching module 203 as shown in FIG. 3 .

The access space determination module 201 is used to determine the access space to be switched based on the received access parameters, and jump from the current access space to EL3; the access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces.

It should be understood that the access space determination module 201 is used to execute the content of the above step 101.

The access space switching setting module 202 is used to save the context of the current access space in EL3 and perform access space switching settings. After the settings are completed, the context of the current access space is restored, and based on the restored context of the current access space, the running program of the access space to be switched is determined; the running program of the secure space and the running program of the non-secure space use a set of codes.

In the present disclosure, the access space switching setting module 202 is also used to obtain the current running program address of the current access space based on the relevant register value of the current access space; and obtain the running program of the access space to be switched based on the current running program address.

The access space switching setting module 202 is also used to set the NS bit of the SCR_EL3 register according to the type of access space to be switched; if the NS bit of the SCR_EL3 register is set to 0, it indicates the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it indicates the access behavior of the non-secure space.

It should be understood that the access space switching setting module 202 is used to execute the content of the above step 102.

The access space switching module 203 is used to enter the access space to be switched based on the running program of the access space to be switched and the switching setting.

It should be understood that the access space switching module 203 is used to execute the content of the above step 103.

Furthermore, the access space switching device 200 provided by the present disclosure also includes: an initialization setting module 204, which is used to perform firmware stack settings for the secure space and the non-secure space before performing the access space switching.

The initialization setting module 204 is further used to set the stack of the secure space and the stack of the non-secure space to be the same stack.

The initialization setting module 204 is also used to configure the same MMU page table for the secure space and the non-secure space.

The initialization setting module 204 is also used to set the NS bit in the MMU page table to 0.

Based on the same inventive concept, an embodiment of the present disclosure also provides a processor, which divides the processor into a secure space, a non-secure space and EL3. The processor switches between the secure space and the non-secure space based on the access space switching method described in any of the above embodiments.

The processor may be a CPU, a GPU, an MCU of a system-on-chip, etc. of an ARMv8 aarch64 architecture.

Based on the same inventive concept, the embodiment of the present disclosure also provides an electronic device, which includes the processor described in any of the above embodiments. In some usage scenarios, the product form of the electronic device is embodied as a graphics card; in other usage scenarios, the product form of the electronic device is embodied as a CPU motherboard.

Based on the same inventive concept, the disclosed embodiment also provides an electronic device, which includes the above-mentioned electronic device. In some usage scenarios, the product form of the electronic device is a portable electronic device, such as a smart phone, a tablet computer, a VR device, etc.; in some usage scenarios, the product form of the electronic device is a personal computer, a game console, etc.

Based on the same inventive concept, an embodiment of the present disclosure further provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the access space switching method described in any of the above embodiments are implemented.

Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims (15)

1. A method for switching an access space, comprising: Determine the access space to be switched based on the received access parameters, and jump from the current access space to EL3; the access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces; In the EL3, the context of the current access space is saved, and the access space switching setting is performed. After the setting is completed, the context of the current access space is restored, and based on the restored context of the current access space, the running program of the access space to be switched is determined; the running program of the secure space and the running program of the non-secure space use a set of codes; Based on the running program of the access space to be switched and the switching setting, enter the access space to be switched. 2. The access space switching method according to claim 1, further comprising: Before switching the access space, a firmware stack is set for the secure space and the non-secure space. 3. The access space switching method according to claim 2, wherein the step of performing firmware stack settings on the secure space and the non-secure space comprises: The stack of the secure space and the stack of the non-secure space are set to be the same stack. 4. The access space switching method according to claim 3, wherein the firmware stack setting for the secure space and the non-secure space further comprises: The same MMU page table is configured for the secure space and the non-secure space. 5. The access space switching method according to claim 4, wherein configuring the same MMU page table for the secure space and the non-secure space comprises: Set the NS bit in the MMU page table to 0. 6. The access space switching method according to claim 1, wherein the step of performing access space switching settings comprises: According to the type of access space to be switched, the NS bit of the SCR_EL3 register is set; if the NS bit of the SCR_EL3 register is set to 0, it indicates the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it indicates the access behavior of the non-secure space. 7. An access space switching device, comprising: An access space determination module, configured to determine an access space to be switched based on received access parameters, and jump from a current access space to EL3; the access space includes a secure space and a non-secure space, and the current access space and the access space to be switched are different access spaces; An access space switching setting module is used to save the context of the current access space in the EL3, and perform access space switching settings, restore the context of the current access space after the settings are completed, and determine the running program of the access space to be switched based on the restored context of the current access space; the running program of the secure space and the running program of the non-secure space use a set of codes; The access space switching module is used to enter the access space to be switched based on the running program of the access space to be switched and the switching setting. 8. The access space switching device according to claim 7, further comprising: The initialization setting module is used to perform firmware stack settings on the secure space and the non-secure space before switching the access space. 9. The access space switching device according to claim 8, wherein the initialization setting module is further used to set the stack of the secure space and the stack of the non-secure space to be the same stack. 10. According to the access space switching device according to claim 9, the initialization setting module is also used to configure the same MMU page table for the secure space and the non-secure space. 11. The access space switching device according to claim 10, wherein the initialization setting module is further used to set the NS bit in the MMU page table to 0. 12. According to the access space switching device of claim 7, the access space switching setting module is also used to set the NS bit of the SCR_EL3 register according to the type of access space to be switched; if the NS bit of the SCR_EL3 register is set to 0, it represents the access behavior of the secure space, and if the NS bit of the SCR_EL3 register is set to 1, it represents the access behavior of the non-secure space. 13. A processor, the processor being divided into a secure space, a non-secure space and EL3, the processor switching between the secure space and the non-secure space based on the access space switching method described in any one of claims 1-6. 14. An electronic device comprising the processor according to claim 13. 15. A storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method according to any one of claims 1 to 6.